FIG. 14 shows a configuration of a conventional portable telephone. The portable telephone includes, as shown, a telephone main body part 9 that demonstrates a function as a portable telephone, and a power source part 90 that serves as a power source of the telephone main body part 9.
A signal received by an antenna 91 is fed to a baseband circuit 93 through an RF circuit 92 and demodulated to a digital reception signal. The digital reception signal is fed to an audio processing circuit 95 and subjected to a predetermined signal processing. An analog reception signal thereby obtained is fed to a speaker 98 and radiated as sound. On the other hand, a transmission signal inputted into a microphone 97 is fed to the audio processing circuit 95 and subjected to a predetermined signal processing. A digital transmission signal thereby obtained is fed to the baseband circuit 93 and modulated. The digital transmission signal modulated is transmitted from the antenna 91 through the RF circuit 92.
Moreover, in addition to a telephone communication function, the above-described portable telephone has a function of downloading various images from a site on the Internet. A digital video signal demodulated in the baseband circuit 93 is fed to a video processing circuit 101 and subjected to a predetermined signal processing. An analog video signal thereby obtained is fed to a display 102. Consequently, the images downloaded from the site on the Internet can be displayed on the display 102.
A CPU 94 is connected through a bus 103 to the above-described baseband circuit 93, audio processing circuit 95 and video processing circuit 101. Connected to the CPU 94 is a key input device 96 including a plurality of manipulation keys. Moreover, connected to the bus 103 are a ROM 100 for storing a program for performing an operation as a portable telephone, and a RAM 99 for storing various pieces of information such as telephone numbers.
On the other hand, the power source part 90 includes a secondary battery 900. Power obtained from the secondary battery 900 is supplied to the above-described circuits included in the telephone main body part 9, so that these circuits perform the above-described predetermined operations.
FIG. 15 shows a configuration of a conventional portable digital broadcast receiver having a recording function. The portable digital broadcast receiver includes, as shown, a receiver main body part 110 that demonstrates a function as a digital broadcast receiver and a power source part 130 that serves as a power source of the receiver main body part 110.
A television broadcast wave received by an antenna 111 is tuned by a tuner 112. A broadcast signal thereby obtained is fed to a CPU 113 and separated into video data and audio data. An audio decoder 114, an audio processing circuit 115, a video decoder 116 and a video processing circuit 117 are connected to the CPU 113 through a bus 123. The video data separated in the CPU 113 is, after fed to the video decoder 116 and decoded, fed to the video processing circuit 117 and subjected to a predetermined signal processing. An analog video signal thereby obtained is fed to a display 119. Consequently, video of a television broadcast program can be projected on the display 119. On the other hand, the audio data separated in the CPU 113 is, after fed to the audio decoder 114 and decoded, fed to the audio processing circuit 115 and subjected to a predetermined signal processing. An analog audio signal thereby obtained is fed to a speaker 118. Consequently, audio of a television broadcast program can be outputted from the speaker 118.
Moreover, connected to the bus 123 are a recording memory 120 for storing the video data and the audio data obtained from the CPU 113 as described above, a ROM 121 for storing a program for performing an operation as a broadcast receiver, and a RAM 122 for storing various pieces of information such as timer recording information.
On the other hand, the power source part 130 includes a secondary battery 131. Power obtained from the secondary battery 131 is supplied to the above-described circuits included in the receiver main body part 110, so that these circuits perform the above-described predetermined operations.
It is possible to add a reception function for digital broadcast to a portable telephone. Such a portable telephone may be configured, for example, by adding the receiver main body part 110 of the digital broadcast receiver shown in FIG. 15 to the portable telephone shown in FIG. 14. However, because the receiver main body part 110 includes many circuits, there is a problem that the portable telephone as a whole becomes large-sized and a weight of the portable telephone as a whole greatly increases. Moreover, there is another problem that power consumption greatly increases because power is supplied to many circuits included in the receiver main body part 110.
An object of the present invention is to provide a portable audio/video playback apparatus with a broadcast receiving function that is as a whole small-sized, light-weighted, and also low power-consuming.